In congestive heart failure or CHF, the heart has become so enlarged as a result of viral infection, myocardial infarction or other disease that it is unable to pump at a sufficient rate to maintain adequate circulation of blood throughout the body. As a result, blood backs up into the lungs, causing shortness of breath and other symptoms, and, if left untreated, the disease can lead to death.
For some patients, the CHF may be treated effectively with medication. However, in many cases, the disease progresses to a point at which the patient requires a heart transplant. Unfortunately, due to a donor shortage, of the 40,000 patients who may require a transplant each year, only 2500 actually get one, with up to 15-20% of patients dying while on the waiting list for a donor heart.
In response to the need for alternatives to transplant for treating CHF, a surgical procedure has been tried in recent years known as the "Batista Operation" after its developer, Dr. Randas J. V. Batista. In this procedure, a large section of the left ventricular wall is excised from the heart and the wall then sewn back together, thereby reducing the transverse dimension and volume of the left ventricle, the primary pumping chamber of the heart. The reduced volume of the ventricle permits less blood to be present in the chamber during each of its contractions, thus reducing the forces acting against the heart muscle as it contracts and allowing the heart to pump more effectively.
Although the Batista Operation can extend the life of a patient who would otherwise die without a transplant, it is a highly invasive and traumatic procedure. In order to expose the heart, the chest must be opened widely by sawing the sternum in half and spreading apart the rib cage, known as a median sternotomy, producing a great deal of pain, risk of infection, and long recovery time. For elderly or extremely ill patients, the trauma produced by the operation could contribute significantly to the mortality and morbidity associated with the procedure.
Moreover, the Batista Operation has typically been performed while the heart is beating, causing a great deal of blood loss through the ventricular incision, and risking the introduction of air into the bloodstream, potentially causing stroke or other neurological problems. To reduce blood loss and the risk of air embolism, the heart could be stopped and isolated from the rest of the circulatory system during the procedure by placing an external aortic cross-clamp on the ascending aorta and using conventional cardioplegia and cardiopulmonary bypass. However, because such cross-clamps crush the walls of the aorta together in order to occlude the vessel, cross-clamps may produce the added risk of releasing calcific particles from the inner walls of the aorta, which may embolize in the bloodstream and produce neurological events such as stroke. Moreover, the risk remains that air will become trapped in the ventricle after it has been closed, allowing the air to migrate to the brain as soon as the cross-clamp is removed. Conventional cross-clamps also require a large opening in the chest in order to gain access to the aorta, hindering any effort to reduce the trauma associated with the procedure.
What arc needed, therefore, arc devices and techniques for the surgical treatment of CHF which are less invasive and less risky than the Batista Operation, but which produce the benefits associated with reducing the volume of the left ventricle. The devices and techniques should facilitate the identification of an appropriate section of the left ventricular wall, excision or other reshaping of the section, and, if the section is removed, closure of the left ventricle, without requiring a gross thoracotomy or median sternotomy. If the left ventricle is opened, the devices and techniques should allow the patient to be placed on cardiopulmonary bypass and the heart to be arrested and isolated from the circulatory system without the need for an external aortic cross-clamp. Further, the devices and techniques should minimize that risk that either air and other emboli will be produced by the procedure.